Objective: To compare the effects of adding and antibiotic (Virginiamycin=VM) or a probiotic (PR a mixed culture of Bacillus subtilis CH 201 and Bacillus licheniformis CH 200) into diet on broiler chicks performance.
Design: Randomized completely design.
Animals: Five hundred and forty day-old male Ross 208 broiler chicks.
Procedure: Three dietary treatments were considered so that each treatment contained six replicate floor pens of 30 chicks. One treatment (as control) received a diet without any antibiotic, growth promotor and coccidiostate. Two other treatments fed diets containing 1.0 g/kg PR or 0.1 g/kg VM, respectively. Feed and water were provided ad-libitum throughort the experimental period. Body weight (BW). feed intake (Fl) and feed conversion ratio (FCR) were determined for each treatments at 21, 42, and 49 days age.
Statistical analysis: Data for all response variables were subjected to ANOVA test. Variable means for treatments showing significant differences in the ANOVA were compared using the Tukey’s test.
Results: At the end of trial, adding VM into diet increased BW significantly (P<0.Ol). while supplemented diet with PR had no significant effect on BW. There was no significant difference between BW of chickens fed diets supplemented with VM or PR. When compared with control, supplementation diets with VM or PR improved FCR, significantly (P<0.01), but no significant differences observed between these two dietary treatments.
Conclusion: Obtained results indicated that adding VM or PR into diets in this experimental trial, caused an improvement in broilers performance in comparison with control. Since there were no significant differences between BW and FCR of chicks fed diet supplemented VM or PR, using PR as a growth promotor in broiler rations could be recommended. .1. Fac. Vet. Med Univ. Tehran. 57, 1: 61-66, 2002.